It was something of a wake-up call for many in Russia. In December 2011, a pair of pretty, articulate, 20-year-old twins from Vladimir Oblast were asked on a television game show, "What is the Holocaust?"

The two consulted together for a few awkward moments. One of them admitted frankly that the term "says nothing to them." Finally, with time running short, Yevgenia Karatygina turns to the camera and says, "We think that the Holocaust is wallpaper paste."

Video of the shocking scene was viewed hundreds of thousands of times online, and it provoked a serious discussion about how the Holocaust is taught in the schools of the country whose troops (along with those of other former Soviet republics) liberated the Nazis' largest concentration and death camp at Auschwitz in Poland.

The sisters -- Yevgenia and Ksenia -- appeared on RFE/RL's Russian Service in March 2012 with Holocaust Fund Chairwoman Alla Gerber. At the time, Yevgenia explained that they were taught a bit about the Holocaust in their school but that the sisters were more interested in other things.

"To be honest, such subjects in school were pretty dull. Not because the teacher was bad -- he knew what he was talking about. But I didn't want to devote my life to that -- I wasn't planning to study at some institute connected with history," Yevgenia said. "So during those lessons I was doing my own thing. I was writing poems. Now we are writing music -- we are into music."

Asked if they had heard of Auschwitz, Yevgenia said no, while Ksenia said: "It is something about some sort of civil war, I think."

In October 2012, with financial support from the Polish Cultural Center in Moscow, documentary filmmaker and former RFE/RL Russian Service correspondent Mumin Shakirov took the sisters on an emotional visit to the museum and memorial complex of Auschwitz-Birkenau in the Polish town of Oswiecim.

Both were deeply moved by the experience. Yevgenia broke down into loud weeping as she stood in front of an enormous pile of children's shoes. Ksenia wept through a showing of the Soviet documentary film "The Liberation Of Auschwitz."

"By coming here, like it or not, we are now among those who know," Ksenia said afterward. "It is shameful that events of this scale [took place], filling a whole stage of history, where Soviet troops participated in the liberation of the prisoners -- and we knew nothing about it."

Shakirov asked the sisters if they would tell their friends and relatives about what they had seen at Auschwitz.

"Hardly anyone we know is interested in things that happened 70 years ago," Ksenia replied. "If they ask, we'll tell them and explain everything. But we won't raise the subject ourselves."